/*
 * Copyright (c) 2011, the Dart project authors.
 * 
 * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.dart.tools.ui.internal.preferences;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceStore;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;

/**
 * An overlaying preference store.
 */
public class OverlayPreferenceStore implements IPreferenceStore {

  public static class OverlayKey {

    TypeDescriptor fDescriptor;
    String fKey;

    public OverlayKey(TypeDescriptor descriptor, String key) {
      fDescriptor = descriptor;
      fKey = key;
    }
  }

  public static final class TypeDescriptor {
    private TypeDescriptor() {
    }
  }
  private class PropertyListener implements IPropertyChangeListener {

    /*
     * @see IPropertyChangeListener#propertyChange(PropertyChangeEvent)
     */
    @Override
    public void propertyChange(PropertyChangeEvent event) {
      OverlayKey key = findOverlayKey(event.getProperty());
      if (key != null) {
        propagateProperty(fParent, key, fStore);
      }
    }
  }

  public static final TypeDescriptor BOOLEAN = new TypeDescriptor();
  public static final TypeDescriptor DOUBLE = new TypeDescriptor();
  public static final TypeDescriptor FLOAT = new TypeDescriptor();
  public static final TypeDescriptor INT = new TypeDescriptor();

  public static final TypeDescriptor LONG = new TypeDescriptor();

  public static final TypeDescriptor STRING = new TypeDescriptor();

  private IPreferenceStore fParent;
  private IPreferenceStore fStore;
  private OverlayKey[] fOverlayKeys;

  private PropertyListener fPropertyListener;
  private boolean fLoaded;

  public OverlayPreferenceStore(IPreferenceStore parent, OverlayKey[] overlayKeys) {
    fParent = parent;
    fOverlayKeys = overlayKeys;
    fStore = new PreferenceStore();
  }

  /**
   * The keys to add to the list of overlay keys.
   * <p>
   * Note: This method must be called before {@link #load()} is called.
   * </p>
   * 
   * @param keys
   */
  public void addKeys(OverlayKey[] keys) {
    Assert.isTrue(!fLoaded);
    Assert.isNotNull(keys);

    int overlayKeysLength = fOverlayKeys.length;
    OverlayKey[] result = new OverlayKey[keys.length + overlayKeysLength];

    for (int i = 0, length = overlayKeysLength; i < length; i++) {
      result[i] = fOverlayKeys[i];
    }

    for (int i = 0, length = keys.length; i < length; i++) {
      result[overlayKeysLength + i] = keys[i];
    }

    fOverlayKeys = result;

    if (fLoaded) {
      load();
    }
  }

  /*
   * @see IPreferenceStore#addPropertyChangeListener(IPropertyChangeListener)
   */
  @Override
  public void addPropertyChangeListener(IPropertyChangeListener listener) {
    fStore.addPropertyChangeListener(listener);
  }

  /*
   * @see IPreferenceStore#contains(String)
   */
  @Override
  public boolean contains(String name) {
    return fStore.contains(name);
  }

  /*
   * @see IPreferenceStore#firePropertyChangeEvent(String, Object, Object)
   */
  @Override
  public void firePropertyChangeEvent(String name, Object oldValue, Object newValue) {
    fStore.firePropertyChangeEvent(name, oldValue, newValue);
  }

  /*
   * @see IPreferenceStore#getBoolean(String)
   */
  @Override
  public boolean getBoolean(String name) {
    return fStore.getBoolean(name);
  }

  /*
   * @see IPreferenceStore#getDefaultBoolean(String)
   */
  @Override
  public boolean getDefaultBoolean(String name) {
    return fStore.getDefaultBoolean(name);
  }

  /*
   * @see IPreferenceStore#getDefaultDouble(String)
   */
  @Override
  public double getDefaultDouble(String name) {
    return fStore.getDefaultDouble(name);
  }

  /*
   * @see IPreferenceStore#getDefaultFloat(String)
   */
  @Override
  public float getDefaultFloat(String name) {
    return fStore.getDefaultFloat(name);
  }

  /*
   * @see IPreferenceStore#getDefaultInt(String)
   */
  @Override
  public int getDefaultInt(String name) {
    return fStore.getDefaultInt(name);
  }

  /*
   * @see IPreferenceStore#getDefaultLong(String)
   */
  @Override
  public long getDefaultLong(String name) {
    return fStore.getDefaultLong(name);
  }

  /*
   * @see IPreferenceStore#getDefaultString(String)
   */
  @Override
  public String getDefaultString(String name) {
    return fStore.getDefaultString(name);
  }

  /*
   * @see IPreferenceStore#getDouble(String)
   */
  @Override
  public double getDouble(String name) {
    return fStore.getDouble(name);
  }

  /*
   * @see IPreferenceStore#getFloat(String)
   */
  @Override
  public float getFloat(String name) {
    return fStore.getFloat(name);
  }

  /*
   * @see IPreferenceStore#getInt(String)
   */
  @Override
  public int getInt(String name) {
    return fStore.getInt(name);
  }

  /*
   * @see IPreferenceStore#getLong(String)
   */
  @Override
  public long getLong(String name) {
    return fStore.getLong(name);
  }

  /*
   * @see IPreferenceStore#getString(String)
   */
  @Override
  public String getString(String name) {
    return fStore.getString(name);
  }

  /*
   * @see IPreferenceStore#isDefault(String)
   */
  @Override
  public boolean isDefault(String name) {
    return fStore.isDefault(name);
  }

  public void load() {
    for (int i = 0; i < fOverlayKeys.length; i++) {
      loadProperty(fParent, fOverlayKeys[i], fStore, true);
    }

    fLoaded = true;

  }

  public void loadDefaults() {
    for (int i = 0; i < fOverlayKeys.length; i++) {
      setToDefault(fOverlayKeys[i].fKey);
    }
  }

  /*
   * @see IPreferenceStore#needsSaving()
   */
  @Override
  public boolean needsSaving() {
    return fStore.needsSaving();
  }

  public void propagate() {
    for (int i = 0; i < fOverlayKeys.length; i++) {
      propagateProperty(fStore, fOverlayKeys[i], fParent);
    }
  }

  /*
   * @see IPreferenceStore#putValue(String, String)
   */
  @Override
  public void putValue(String name, String value) {
    if (covers(name)) {
      fStore.putValue(name, value);
    }
  }

  /*
   * @see IPreferenceStore#removePropertyChangeListener(IPropertyChangeListener)
   */
  @Override
  public void removePropertyChangeListener(IPropertyChangeListener listener) {
    fStore.removePropertyChangeListener(listener);
  }

  /*
   * @see IPreferenceStore#setDefault(String, boolean)
   */
  @Override
  public void setDefault(String name, boolean value) {
    if (covers(name)) {
      fStore.setDefault(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setDefault(String, double)
   */
  @Override
  public void setDefault(String name, double value) {
    if (covers(name)) {
      fStore.setDefault(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setDefault(String, float)
   */
  @Override
  public void setDefault(String name, float value) {
    if (covers(name)) {
      fStore.setDefault(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setDefault(String, int)
   */
  @Override
  public void setDefault(String name, int value) {
    if (covers(name)) {
      fStore.setDefault(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setDefault(String, long)
   */
  @Override
  public void setDefault(String name, long value) {
    if (covers(name)) {
      fStore.setDefault(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setDefault(String, String)
   */
  @Override
  public void setDefault(String name, String value) {
    if (covers(name)) {
      fStore.setDefault(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setToDefault(String)
   */
  @Override
  public void setToDefault(String name) {
    fStore.setToDefault(name);
  }

  /*
   * @see IPreferenceStore#setValue(String, boolean)
   */
  @Override
  public void setValue(String name, boolean value) {
    if (covers(name)) {
      fStore.setValue(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setValue(String, double)
   */
  @Override
  public void setValue(String name, double value) {
    if (covers(name)) {
      fStore.setValue(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setValue(String, float)
   */
  @Override
  public void setValue(String name, float value) {
    if (covers(name)) {
      fStore.setValue(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setValue(String, int)
   */
  @Override
  public void setValue(String name, int value) {
    if (covers(name)) {
      fStore.setValue(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setValue(String, long)
   */
  @Override
  public void setValue(String name, long value) {
    if (covers(name)) {
      fStore.setValue(name, value);
    }
  }

  /*
   * @see IPreferenceStore#setValue(String, String)
   */
  @Override
  public void setValue(String name, String value) {
    if (covers(name)) {
      fStore.setValue(name, value);
    }
  }

  public void start() {
    if (fPropertyListener == null) {
      fPropertyListener = new PropertyListener();
      fParent.addPropertyChangeListener(fPropertyListener);
    }
  }

  public void stop() {
    if (fPropertyListener != null) {
      fParent.removePropertyChangeListener(fPropertyListener);
      fPropertyListener = null;
    }
  }

  private boolean covers(String key) {
    return (findOverlayKey(key) != null);
  }

  private OverlayKey findOverlayKey(String key) {
    for (int i = 0; i < fOverlayKeys.length; i++) {
      if (fOverlayKeys[i].fKey.equals(key)) {
        return fOverlayKeys[i];
      }
    }
    return null;
  }

  private void loadProperty(IPreferenceStore orgin, OverlayKey key, IPreferenceStore target,
      boolean forceInitialization) {
    TypeDescriptor d = key.fDescriptor;
    if (BOOLEAN == d) {

      if (forceInitialization) {
        target.setValue(key.fKey, true);
      }
      target.setValue(key.fKey, orgin.getBoolean(key.fKey));
      target.setDefault(key.fKey, orgin.getDefaultBoolean(key.fKey));

    } else if (DOUBLE == d) {

      if (forceInitialization) {
        target.setValue(key.fKey, 1.0D);
      }
      target.setValue(key.fKey, orgin.getDouble(key.fKey));
      target.setDefault(key.fKey, orgin.getDefaultDouble(key.fKey));

    } else if (FLOAT == d) {

      if (forceInitialization) {
        target.setValue(key.fKey, 1.0F);
      }
      target.setValue(key.fKey, orgin.getFloat(key.fKey));
      target.setDefault(key.fKey, orgin.getDefaultFloat(key.fKey));

    } else if (INT == d) {

      if (forceInitialization) {
        target.setValue(key.fKey, 1);
      }
      target.setValue(key.fKey, orgin.getInt(key.fKey));
      target.setDefault(key.fKey, orgin.getDefaultInt(key.fKey));

    } else if (LONG == d) {

      if (forceInitialization) {
        target.setValue(key.fKey, 1L);
      }
      target.setValue(key.fKey, orgin.getLong(key.fKey));
      target.setDefault(key.fKey, orgin.getDefaultLong(key.fKey));

    } else if (STRING == d) {

      if (forceInitialization) {
        target.setValue(key.fKey, "1"); //$NON-NLS-1$
      }
      target.setValue(key.fKey, orgin.getString(key.fKey));
      target.setDefault(key.fKey, orgin.getDefaultString(key.fKey));

    }
  }

  private void propagateProperty(IPreferenceStore orgin, OverlayKey key, IPreferenceStore target) {

    if (orgin.isDefault(key.fKey)) {
      if (!target.isDefault(key.fKey)) {
        target.setToDefault(key.fKey);
      }
      return;
    }

    TypeDescriptor d = key.fDescriptor;
    if (BOOLEAN == d) {

      boolean originValue = orgin.getBoolean(key.fKey);
      boolean targetValue = target.getBoolean(key.fKey);
      if (targetValue != originValue) {
        target.setValue(key.fKey, originValue);
      }

    } else if (DOUBLE == d) {

      double originValue = orgin.getDouble(key.fKey);
      double targetValue = target.getDouble(key.fKey);
      if (targetValue != originValue) {
        target.setValue(key.fKey, originValue);
      }

    } else if (FLOAT == d) {

      float originValue = orgin.getFloat(key.fKey);
      float targetValue = target.getFloat(key.fKey);
      if (targetValue != originValue) {
        target.setValue(key.fKey, originValue);
      }

    } else if (INT == d) {

      int originValue = orgin.getInt(key.fKey);
      int targetValue = target.getInt(key.fKey);
      if (targetValue != originValue) {
        target.setValue(key.fKey, originValue);
      }

    } else if (LONG == d) {

      long originValue = orgin.getLong(key.fKey);
      long targetValue = target.getLong(key.fKey);
      if (targetValue != originValue) {
        target.setValue(key.fKey, originValue);
      }

    } else if (STRING == d) {

      String originValue = orgin.getString(key.fKey);
      String targetValue = target.getString(key.fKey);
      if (targetValue != null && originValue != null && !targetValue.equals(originValue)) {
        target.setValue(key.fKey, originValue);
      }

    }
  }
}
